The disclosure of Japanese Patent Application No. 2001-110239 filed on Apr. 9, 2001 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
This invention relates to an internal combustion engine equipped with a regenerator.
2. Description of the Related Art
Generally, when an internal combustion engine is running at temperatures under a predetermined temperature around combustion chambers, fuel atomization supplied to the combustion chambers deteriorates and so did exhaust gas emission due to quenching around walls of the combustion chambers.
In order to obviate this problem, an internal combustion engine equipped with a regenerator is being developed which can accumulate heat generated from combustion when the engine is running. Then the accumulated heat is supplied to the engine when the engine is not running or the engine needs to be started. However, the amount of heat accumulated in the regenerator is limited, then a technology which utilizes the limited amount of heat effectively is being disclosed.
According to Japanese patent application Laid-open No. 6-185359, the engine is equipped with a first coolant channel which supplies water coolant to a cylinder block, a second coolant channel which supplies coolant to a cylinder head independently and is connected to a regenerator.
A regenerator in the internal combustion engine which is formed according to the above prior technology supplies heat to the cylinder head intensively through the second coolant channel. The heat is emitted from the regenerator when the engine is under cold conditions. As mentioned above, the limited amount of heat can be supplied to the internal combustion engine effectively by supplying the heat accumulated in the regenerator to a cylinder head intensively. Therefore, emission performance and fuel efficiency can be improved.
However, a coolant channel, which is connected to the cylinder head and the cylinder block, flows into both the cylinder head and the cylinder block. Water coolant flows into devices such as a radiator and a heater core which are located outside the internal combustion engine since some of the water coolant channels are connected to these devices. If heat is supplied to a part where heat supply is not needed, the temperature of coolant drops unnecessarily which increases heat consumption in the regenerator. If a regenerator with large volume is to be installed in a vehicle, a quite large device is needed which makes the installation difficult. Even if the installation is possible, fuel consumption and automobile performance deteriorates due to the increased mass.
In this connection, an internal combustion engine needs to be warmed up before being started to start the internal combustion engine under warm conditions. However, it is difficult to precisely grasp the timing of starting the engine. Therefore, heat needs to be supplied to the internal combustion engine for a long period, when the timing of starting the engine is being delayed for some reason. The amount of heat accumulated in the regenerator is limited, and therefore it is important to utilize the heat effectively to supply heat to the internal combustion engine for a long period.
It is an object of the invention to provide a technology to supply heat to an internal combustion engine for a long period even when the internal combustion engine is turned off. Therefore, deterioration of exhaust emission can be prevented.
According to a first aspect of the invention, an internal combustion engine is equipped with an engine body, which includes a cylinder head and a cylinder block, and a regenerator which accumulates heat. The internal combustion engine further includes a circulation system which circulates a heat medium, a cylinder head part channel which circulates the heat medium into the cylinder head, a cylinder block part channel which circulates the heat medium into the cylinder block, a connecting channel which connects the cylinder head part channel with the cylinder block part channel, a heat supply device that supplies heat accumulated in the regenerator to the internal combustion engine through the heat medium in the circulation channel, and a restraining device that restrains heat circulation in the connecting channel when heat is supplied by the heat supply device or the internal combustion engine is under cold conditions.
In an internal combustion engine equipped with a regenerator according to the first aspect, the heat, which is generated when the internal combustion engine is running, is stored by the regenerator even after the internal combustion engine is turned off. The heat accumulated by the regenerator circulates into the circulation system through the heat medium. The heat medium passes the cylinder block part channel, the connecting channel, and the cylinder head part channel, all of which are provided in the internal combustion engine, after reaching the internal combustion engine. At this time, the heat medium supplies heat to the internal combustion engine.
As described above, the regenerator loses heat by supplying heat to the internal combustion engine. On the other hand, the heat is supplied to the internal combustion engine so that the temperature of the internal combustion engine rises even before the internal combustion engine is starting.
The restraining device restrains circulation of the heat medium in the connecting channel and in a part where heat supply is not needed in the internal combustion engine. For example, components of the internal combustion engine can be arranged in the way that the heat medium does not circulate in the cylinder block part channel since it is effective to mainly warm the cylinder head part to restrain deterioration of the exhaust gas emission.
As described above, the limited amount of heat accumulated in a regenerator can be supplied to an internal combustion engine for long period by restraining unnecessary heat consumption. Furthermore, downsizing a regenerator and shortening time to supply heat have been made possible.
The restraining device can be arranged in the way that circulation of the heat medium is shut off completely or can be a diaphragm through which the heat medium can circulate to a certain extent. Also, the restraining device can include a throttle valve which controls the amount of heat medium circulation or can be a thermostat valve which automatically opens and closes according to temperatures of the heat medium. Furthermore, the restraining device can be a electromagnetic valve which controls opening and closing the valve from outside of an internal combustion engine.
The restraining device can cancel restraining circulation of the heat medium when an internal combustion engine has started. The cancel can be conditioned on a period before and after starting an internal combustion engine or on that a certain time passes after starting an engine. Furthermore, the cancel can be conditioned on that the heat medium reaches a certain temperature.
According to a second aspect of the invention, an internal combustion engine is equipped with an engine body, which includes a cylinder head and a cylinder block, and a regenerator which accumulates heat. The internal combustion engine further includes a circulation system which circulates the heat medium, a cylinder head part channel which circulates the heat medium into the cylinder head, a cylinder block part channel which circulates the heat medium into the cylinder block, a connecting channel which connects the cylinder head part channel with the cylinder block part channel, a heat supply device that supplies the heat accumulated in the regenerator to the internal combustion engine through the heat medium in the circulation channel, and a circulation direction restraining device that restrains circulation directions of the heat medium in the connecting channel.
In an internal combustion engine equipped with a regenerator according to the second aspect, the heat, which is generated when the internal combustion engine is running, is stored by the regenerator even after the internal combustion engine is turned off. The heat accumulated by the regenerator circulates into the circulation system through the heat medium. The heat medium passes the cylinder block part channel, the connecting channel, and the cylinder head part channel, all of which are provided in the internal combustion engine, after reaching the internal combustion engine. At this time, the heat medium supplies heat to the internal combustion engine.
As described above, the regenerator loses heat by supplying heat to the internal combustion engine. On the other hand, the heat is supplied to the internal combustion engine so that the temperature of the internal combustion engine rises even before the internal combustion engine is starting.
The circulation direction restraining device restrains circulation directions of the heat medium in the connecting channel and in a part where heat supply is not needed in the internal combustion engine.
As described above, limited amount of heat accumulated in a regenerator can be supplied to an internal combustion engine for long period by restraining unnecessary heat consumption. Furthermore, downsizing a regenerator and shortening time to supply heat have been made possible.
The circulation direction restraining device restrains circulating the heat medium from a part where heat supply is needed to a part where heat supply is not needed in the internal combustion engine. On the other hand, the circulation direction restraining device does not restrain circulating the heat medium from a part where heat supply is not needed to a part where heat supply is needed. The above-mentioned fact is especially effective when the circulation directions of the heat medium are the opposite depending on whether heat is supplied from the regenerator or the internal combustion engine is running.
The circulation direction restraining device can be arranged in the way that circulation of the heat medium is shut off completely or in the way that the heat medium can circulate to a certain extent. Furthermore, the circulation direction restraining device can be arranged to control circulation amount of the heat medium.
The circulation direction restraining device can cancel restraining circulation of the heat medium when an internal combustion engine has started. The cancel can be conditioned on a period before and after starting an internal combustion engine or on that a certain time passes after starting an engine. Furthermore, the cancel can be conditioned on that the heat medium reaches a certain temperature.
In an internal combustion engine equipped with a cylinder head and a cylinder block according to the second aspect described above, the circulation direction restraining device can be arranged in the way that circulation of the heat medium from the cylinder head to the cylinder block is restrained.
In an internal combustion engine with a regenerator according to the above aspect, circulation of the heat medium from a cylinder head to a cylinder block can be restrained when heat is supplied from the regenerator. Therefore, unnecessary heat supply at the cylinder block can be restrained.
According to a third aspect of the invention, an internal combustion engine is equipped with a regenerator. The internal combustion engine further includes a circulation system which circulates the heat medium, a heat supply device that supplies heat accumulated in the regenerator to the internal combustion engine through the heat medium in the circulation system, a heat exchanger that lowers the temperature of the heat medium by conducting heat, and a connecting restraint device that restrains circulation of the heat medium in the heat exchanger when heat is supplied by the heat supply device or the internal combustion engine is under cold conditions.
In an internal combustion engine equipped with a regenerator, according to the third aspect, the heat, which is generated when the internal combustion engine is running, is stored by the regenerator even after the internal combustion engine is turned off. The heat accumulated by the regenerator circulates into the circulation system through the heat medium. The heat medium passes the cylinder block part channel, the connecting channel, and the cylinder head part channel, all of which are provided in the internal combustion engine, after reaching the internal combustion engine. At this time, the heat medium supplies heat to the internal combustion engine.
The heat exchanger is connected to the internal combustion engine through the circulation channel. The internal combustion engine, whose temperature is raised during running, emits heat to the heat medium. The heat medium, which is supplied heat, reaches the heat exchanger after the circulation system. The heat medium emits its heat at the heat exchanger which enables the heat medium to accept heat supply again.
However, when heat is supplied from the regenerator to the internal combustion engine and the heat medium passes the heat exchanger, the heat accumulated in the regenerator is emitted from the heat exchanger. The amount of heat which can be supplied to a part where heat supply is needed decreases when the heat is emitted from the heat exchanger since the amount of heat which can be accumulated in the regenerator is limited. Especially when the period from the beginning of heat supply to the start of the internal combustion engine is prolonged, the amount of heat decreases since the heat supply may repeat and the heat is emitted from the heat exchanger as a result of each heat supply. Then the period of possible supplying heat to the internal combustion engine is shortened.
To obviate the above-mentioned problem, the connecting restraint device restrains circulation of the heat medium in the circulation channel located between the internal combustion engine and the heat exchanger. The connecting restraint device can be arranged in the way that circulation of the heat medium is shut off completely or can be a diaphragm through which the heat medium can circulate to a certain extent. Also, the connecting restraint device can include a throttle valve which controls the amount of heat medium circulation.
The connecting restraint device can cancel restraining circulation of the heat medium when an internal combustion engine has started. The cancel can be conditioned on a period before and after starting an internal combustion engine or on that a certain time passes after starting an engine. Furthermore, the cancel can be conditioned on that the heat medium reaches a certain temperature.
The heat exchanger can be a heater for a vehicle compartment according to the invention.
According to a fourth aspect of the invention, an internal combustion engine is equipped with a regenerator. The internal combustion engine further includes a circulation system which circulates the heat medium, a heat supply device that supplies heat accumulated in the regenerator to the internal combustion engine through the heat medium in the circulation system, a bypass channel which connects a part on the side of the inlet of the internal combustion engine with a part on the side of the outlet of the internal combustion engine, a temperature controller that reintroduces the heat medium, which circulates into the internal combustion engine when the internal combustion engine is under cold conditions, to the internal combustion engine through the bypass channel, and a connecting restraint device that restrains circulation of the heat medium in the bypass channel when heat is supplied from the regenerator.
In an internal combustion engine equipped with a regenerator according to the fourth aspect, the heat, which is generated when the internal combustion engine is running, is stored by the regenerator even after the internal combustion engine is turned off. The heat accumulated by the regenerator circulates into the circulation system through the heat medium. The heat medium passes the cylinder block part channel, the connecting channel, and the cylinder head part channel, all of which are provided in the internal combustion engine, after reaching the internal combustion engine. At this time, the heat medium supplies heat to the internal combustion engine.
It is important to rapidly raise the temperature of the internal combustion engine since the exhaust emission may deteriorate when the temperature of the internal combustion engine is low right after starting. Then, the temperature controller circulates the heat medium into the internal combustion engine through the bypass channel not to emit the heat, which is emitted by the internal combustion engine, through a device such as the heat exchanger. As described above, rapid raising temperature of the internal combustion engine is possible.
However, when heat is supplied from the regenerator to the internal combustion engine and some of the heat medium circulates into the bypass channel, the heat from the heat medium in the bypass channel is not supplied to the internal combustion engine. Therefore, the amount of heat supplied to the internal combustion engine is decreased. Under this condition, the effect of heat supply from the regenerator is decreased.
The connecting restraint device can increase the effect of heat supply by restrain circulating the heat medium into the bypass channel. The connecting restraint device can be arranged in the way that circulation of the heat medium is shut off completely or can be a diaphragm through which the heat medium can circulate to a certain extent. Also, the connecting restraint device can include a throttle valve which controls the amount of heat medium circulation.
The connecting restraint device can cancel restraining circulation of the heat medium when an internal combustion engine has started. The cancel can be conditioned on a period before and after starting an internal combustion engine or on that a certain time passes after starting an engine. Furthermore, the cancel can be conditioned on that the heat medium reaches a certain temperature.
According to the third and fourth aspects, the connecting restraint device can be a thermostat valve which opens at a predetermined temperature or above.
According to the third and fourth aspects, the connecting restraint device can be a pressure-sensing valve which opens according to a difference in pressure of the heat medium before and after the connecting restraint device.
According to the third and fourth aspects, the connecting restraint device can be a one-way valve which opens when the valve receives pressure in a predetermined direction.
According to the third and fourth aspects, the connecting restraint device can be a electromagnetic opening and closing valve.
According to a fifth aspect of the invention, an internal combustion engine is equipped with a regenerator. The internal combustion engine further includes a circulation system which circulates the heat medium, a heat supply device that supplies heat accumulated in the regenerator to the internal combustion engine through the heat medium in the circulation system, a bypass channel which connects a part on the side of the inlet of the internal combustion engine with a part on the side of the outlet of the internal combustion engine, and a temperature controller that introduces the heat medium, which circulates into the internal combustion engine when the internal combustion engine is under cold conditions, to the internal combustion engine again through the bypass channel. Furthermore, the bypass channel includes the regenerator.
In an internal combustion engine equipped with a regenerator according to the fifth aspect, the heat, which is generated when the internal combustion engine is running, is stored by the regenerator even after the internal combustion engine is turned off. The heat accumulated by the regenerator circulates into the circulation system through the heat medium. The heat medium passes the cylinder block part channel, the connecting channel, and the cylinder head part channel, all of which are provided in the internal combustion engine, after reaching the internal combustion engine. At this time, the heat medium supplies heat to the internal combustion engine.
The bypass channel connects a part through which the heat medium flows into the internal combustion engine with a part through which the heat medium flows out of the internal combustion engine.
It is important to rapidly raise the temperature of the internal combustion engine since the exhaust emission may deteriorate when the temperature of the internal combustion engine is low right after starting. Then, the temperature controller circulates the heat medium into the internal combustion engine through the bypass channel until the heat medium reaches a predetermined temperature not to emit the heat, which is emitted by the internal combustion engine, through a device such as the heat exchanger. As described above, rapid raising temperature of the internal combustion engine is possible.
According to the fifth aspect, the circulation system, which circulates the heat medium, and the bypass channel, which circulates the heat medium when the temperature of the heat medium is low and the internal combustion engine is running, are in common.
According to the fifth aspect, heat can be supplied to the internal combustion engine no matter whether the internal combustion engine is running or not. And simplification of the device is possible.